Pituitary Adenoma

By Dr mazhar ali

Did you know??

• Robert Wadlow was the tallest recorded man on earth at a height of 8 ft 11 in.

• His astounding height was the result of a pituitary tumor

Anatomy

• Located immediately under the hypothalamus

• Rests on the Pituitary fossa (sella turcica)

• Comprised of two lobes; anterior (adenohypohpysis) and posterior (neurohypophysis)

• The lobes are separated by an intermediate lobe

Function

• This organ is part of the endocrine system• Once thought of as the “master gland” the

pituitary gland is actually controlled by the hypothalamus

• Sends many hormones to glands throughout the body

PITUITARY ADENOMA

• Pituitary adenomas are a collection of tumors that arise from the pituitary gland. They are the most common cause of Optic chiasm compression. Ophthalmologic pathology typically involves Visual field defects, although less commonly patients may also have Ocular motility deficits and/or Diplopia, certain forms of Nystagmus, signs and symptoms of Increased intracranial pressure due to mass effect, Optic atrophy.

CLASSIFICATION

Size,• Macroadenomas: ≥10 mm• Microadenomas: <10 mmHormonal activityFunctional (secreting) tumorNonfunctional (nonsecreting) tumorsStaining patternAcidophils ……………… acid fuschinBasophils………………… aniline blue. Chromophobes … contain agranular cytoplasm.

Symptoms

• Headaches• Vision Problems• Visual Disturbances• Nausea• Vomiting

PITUITARY ADENOMA(BASOPHIL)

• Basophil tumours secrete ACTH and cause Cushing disease

• (Cushing syndrome refers to the clinical picture due to any cause of increased blood cortisol).

SIGNs

a    Obesity may be generalized or classically involve the trunk, abdomen and neck (‘buffalo hump’).   b    The face is swollen (‘moon face’) females may be hirsute    c    The skin is thin and susceptible to bruising. Purple striae may be seen Hyperpigmentation may develop with ACTH-dependent Cushing syndrome    d    Other features depression/psychosis, osteoporosis, slow wound healing and proximal myopathy.

Ophthalmic features

• Bitemporal hemianopia is uncommon with secreting pituitary adenomas, which tend to present with systemic features of hypersecretion,

• As opposed to non-secreting pituitary tumours, which tend to present with chiasmal compression

COMPLICATION

include • hypertension, • diabetes, • pathological fractures and acute necrosis of

the femoral head

INVESTIGATION

• In Cushing syndrome are targeted at first establishing the presence of elevated cortisol levels

• then identifying the underlying cause (unless iatrogenic); they are best undertaken by an endocrinologist.

TREATMENT

•   a    Surgical removal of pituitary adenoma or adrenal secreting tumour. Ectopic foci of ACTH secretion may also be amenable to excision.

•   b    Medical suppression of cortisol secretion with metyrapone or aminoglutethimide.

PITUITARY ADENOMA(ACIDOPHILIC)

• Acidophil tumours cause gigantism in children and acromegaly in adults.

• Acromegaly is caused by excessive growth hormone (GH) occurring during adult life, after epiphyseal closure and is almost invariably due to a secreting pituitary acidophil adenoma (hypersecretion of growth hormone in childhood, prior to epiphyseal closure, results in gigantism).

SIGNs

•   a    Skin. Hyperhidrosis, acne and hirsutism in females.   b    Face    •    thick lips, exaggerated nasolabial folds, prominent supraorbital ridges    •    Enlargement of the jaw with dental malocclusion

   c    Enlargement of the head hands, feet, tongue and internal organs.

Ophthalmic features

• a    Common. Bitemporal hemianopia and optic atrophy.   b    Rare. Angioid streaks and see-saw nystagmus of Maddox.

INVESTIGATION

• The diagnosis may be confirmed by measuring GH levels in response to an oral glucose tolerance test.

• Normal individuals manifest suppression of GH levels to below 2mU/L. However, in acromegaly, GH levels do not fall, and may paradoxically rise.

TREATMENT

• Treatment options include• Bromocriptine (a long-acting dopamine

agonist),• Radiotherapy (external beam or by

implantation of yttrium rods in the pituitary) and

• Trans-sphenoidal hypophysectomy.

PITUITARY ADENOMA(CHROMOPHOBE)• Chromophobe adenomas may secrete

prolactin and are referred to as prolactinomas

• in men they cause hypogonadism, impotence, sterility, decreased libido, and occasionally gynaecomastia

• Chromophobe adenoma is the most common primary intracranial tumour to produce neuro-ophthalmological features.

PRESENTATION

• Head ache due to involvement of pain-sensitive fibres in the diaphragma sellae

• Visual field defects depend on the anatomical relationship between the pituitary and chiasm.    •    If the chiasm is central, both superotemporal fields are affected first, as the tumour grows upwards and splays the anterior chiasmal notch, compressing the crossing inferonasal fibres    •    The defects then progress into the lower temporal fields. As tumour growth is often asymmetrical, the degree of visual field loss is usually different on the two sides.   •    Patients may not present until central vision is affected from pressure on the macular fibres.

• Optic atrophy is present in approximately 50% of cases with field defects caused by pituitary lesions

• Extensive loss of the temporal visual field in both eyes can disrupt sensory fusion, decompensate a phoria or cause problems with near vision. ‘Postfixation blindness’ refers to the presence of a blind area distal to the fixation point.

• Miscellaneous features include diplopia as a result of lateral expansion into the cavernous sinus and involvement of ocular motor nerves and, rarely, see-saw nystagmus

Special investigations of pituitary adenomas• MR demonstrates the relationship between a

mass lesion and the chiasm• CT will demonstrate enlargement or erosion

of the sella• Endocrinological evaluation All patients

suspected of having a pituitary adenoma should have assays of serum prolactin, FSH, TSH and growth hormone

Prevention

There are no known ways to prevent pituitary cancer, but there are ways to lower your chances of getting any kind of cancer, and to kill it early if you do get cancer. Such methods include:

1. Know your family’s health history, and take note of any signs that could be a sign of cancer.

2. Eat well, and stay active.3. Avoid extensive exposure to harmful substances such as

chemicals and even the sun.